Device for conveying oscillating axial motions to a rotatable roller

ABSTRACT

A device for conveying oscillating axial motions to a roller being rotatable around a geometrical main axis of rotation, includes a reduction gear that is connectable to the roller and connected to a transmission member being moveable axially to-and-fro and to a rotor being rotatably journalled in a holder, around a secondary axis of rotation (S) via a hinge radially spaced from the main axis of rotation, the hinge being planetary moveable in a path, whose angle relative to the main axis of rotation determines the axial length of stroke of the transmission member and of the roller. The reduction gear and transmission member are housed in a housing that has a fixed wall shell and a casing serving as holder for the rotor, the casing being turnable relative to the wall shell to provide readjustment of the axial length of stroke of the roller.

TECHNICAL FIELD OF THE INVENTION

This invention relates to a device for conveying oscillating axialmotions to a roller which is rotatable around a geometrical main axis ofrotation and which is journalled in a frame, comprising a reductiongear, which is connectable to the roller and connected to a transmissionmember being rotatable around the main axis of rotation andsimultaneously moveable axially to-and-fro in order to gear down therotation of the roller to a slower rotation of the transmission member,said transmission member being connected to a rotor being rotatablyjournalled in a holder around a secondary geometrical axis of rotation,via a hinge being radially spaced from the main axis of rotation, saidhinge being planetary movable in a path, the angle of which relative tothe main axis of rotation determines the axial length of stroke of thetransmission member and thereby the axial length of stroke of theroller.

PRIOR ART

In offset printing presses, dampening apparatus and inking devices,respectively, are included, which have the object of feeding differentliquids to a printing plate, which is wound on a cylinder or roller. Inorder to attain a good printing result, it is required that theapplication of damp and ink, respectively, to the printing plate iscontrollable and possible to keep even per unit area so that capturingof ink by the printing plate is solely determined by the screen densityof the plate and not by irrelevant parameters. For this purpose,relatively intricate systems of rollers from a primary source of liquid,e.g. a damp box or an ink box, to the printing plate roller areutilized. This printing plate roller has to have a relatively largecircumference in order to correspond to the format of the paper to beprinted. The other rollers may advantageously be of a considerablysmaller diameter. Grade defects tend to occur, inter alia, by the factthat even dyeing of the inking cylinder that finally is to transfer theink to the printing plate is constantly disrupted by virtue of the inkbeing consumed, i.e. transferred to the printing plate, in an uneven wayalong the envelope surface thereof, viz. where one or more printingareas (e.g. a blue sky in an advertisement) are located. For this reasonlocal shortage of ink at the inking cylinder intermittently occurs, andthis shortage has to be remedied (i.e. refilled) before the same surfaceof the inking cylinder is brought into contact with the printing platethe next time.

A radical way of trying to solve this problem is to scrape off allnon-transferred ink on the inking cylinder at each turn of revolution,whereupon an entirely new layer of ink is applied from scratch. Aninking device that operates in this manner is denominated ANILOX inkingdevice. However, such inking devices have a number of disadvantages thathave prevented the break through of the technique.

The predominant inking devices on the market operate with variousprocedures of eliminating the disadvantages of insufficient rate ofreplenishing of ink according to above. One way is to use a plurality(e.g. 2 to 4) of inking cylinders having different diameters. Then, eacherror is divided into a plurality of smaller partial errors that aredisplaced relative to each other, at least in the circumferentialdirection. In order to equalize the lateral errors, oscillating rollersare utilized in inking devices as well as in damping apparatus. Suchrollers spread or even out the ink and water film, respectively, in thelongitudinal direction of the roller while the roller rotates.

In the technical area in question, two different principal types ofdevices to attain axial oscillation are found, viz., on one hand,devices that are internally mounted in the rollers, and, on the otherhand, devices that are externally mounted on the frame carrying therollers.

Examples of oscillation devices of the internal type are disclosed in WO93/06999 (see also U.S. Pat. No. 5,704,865), SE 9302892-6 (publicationnumber 501 751) and U.S. Pat. No. 5,429,050.

In practice, however, the most frequently occurring oscillation devicesare of the external type, i.e. the devices are mounted on the outside ofone of two frame plates between which the oscillatable roller extends,the individual device being connected to a trunnion protruding from anend of the roller. Examples of external oscillation devices aredisclosed in U.S. Pat. No. 4,753,167, U.S. Pat. No. 5,309,833 and SE 187854. However, a disadvantage of these previously known devices is thatthey are fairly voluminous, which causes component collisions when adrive chain from the ink capturing fountain roller of the inking deviceto the printing plate roller is to be constructed. Space demandingoscillation devices are of particular inconvenience as a consequence ofthe design engineer frequently needing to be able to design a number ofalternative versions of a principal design. Another disadvantage ofpreviously known, external oscillation devices is that readjustment ofthe length of stroke of the oscillatory motions only can be effected ina manual way, which in practice implies that the printing presses has tobe shut down for a relatively long time. Furthermore, the previouslyknown oscillation devices are constructed with expensive lubricationsystems and placed in spaces subjected to open splash lubrication,something that among other things entails a certain risk of oilcontamination of other parts of the press. Yet another disadvantage ofthe known oscillation devices is that they are of an intricate designand consist of many separate components. In practice, this entails thatthe devices will be expensive to manufacture and maintain.

OBJECTS AND FEATURES OF THE INVENTION

The present invention aims at obviating the above-mentioneddisadvantages of previously known oscillation devices and at providingan improved oscillation device of the external type. A primary object ofthe invention, therefore, is to provide an oscillation device that ismountable externally on a roller frame and has a minimal volume, so asto make it possible to build-in the same into many different types ofprinting presses without causing component collisions that will restrainthe design engineers freedom while designing load transmissions fordifferent types of printing presses. In particular it is endeavouredthat the vital outer dimensions of the oscillation device should notexceed the own outer diameter of the oscillating roller. Furthermore,the device should be possible to manufacture as a freestanding unit oras a standard component that allows to be freely installed in arbitraryprinting presses without the component manufacturer need to know aboutthe structure of the individual printing press in advance. Anotherobject of the invention is to provide an oscillation device that in itsentirety is enclosed in a sealed housing from which there is no risk oflubricant splashing or leaking out in the surroundings. Furthermore, thedevice should be possible to manufacture in an uncomplicated andinexpensive manner. In addition, in a particular aspect, the inventionaims at providing an oscillation device, the length of stroke of whichcan be controlled remotely, suitably in such a way that the readjustmentthereof can be effected during operation, all with the object ofminimising or entirely eliminating the need of shutting down the presswhen an alteration of the oscillation amplitude of the roller isdesired. Furthermore, the readjustment should be possible to accomplishin a rapidly and accurately manner by means of elementary mechanicalmeans.

According to the invention at least the primary object is attained bymeans of the features that are stated in the characterising part ofclaim 1. Advantageous embodiments of the invention are further definedin the dependent claims.

Further Demonstration of Prior Art

An oscillation device of the type defined in the preamble of thefollowing claim 1 is previously known through above-mentioned SE 187854. However, in this case, the parts being included in the device arenot at all housed in any splash-proof housing and even less in anyhousing with a turnable casing to attend readjustment of the length ofstroke of the roller. At the known device the reduction gear consists ofa space-requiring planetary gear with a plurality of planet wheels, oneof which serve as a transmission member. Another disadvantage is thatthe holder for the rotor (in the shape of a cylindrical sleeve) carryingthe planetary movable hinge, constitute of a tilted stud, which is heldfixed in a desired angle position by means of a lock nut. In other wordsthe readjustment of the length of stroke of the roller can solely beeffected in a manual way after detaching the lock nut.

BRIEF DESCRIPTION OF THE APPENDED DRAWINGS

In the drawings:

FIG. 1 is a schematic side view illustrating a drive chain between afountain roller and a printing plate roller in an inking device of anoffset printing press,

FIG. 2 is a longitudinal section through an oscillation device accordingto the invention, said device being connected to an individual rollerand shown set in a starting position in which the oscillation amplitudeof the roller is equal to zero,

FIG. 3 is an analogous longitudinal section showing a casing included inthe device and readjusted so that the roller obtain maximum oscillationamplitude or length of stroke,

FIG. 4 is a corresponding longitudinal section showing the rollerrotated half a revolution relative to the position of rotation accordingto FIG. 3,

FIG. 5 is an enlarged, partial longitudinal section showing only theleft part of the device, more precisely in the same state as in FIG. 4,

FIG. 6 is a longitudinal section through an alternative embodiment ofthe device, and

FIG. 7 is an enlarged detail section A in FIG. 6.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

In FIG. 1, a drive chain to an inking device is schematically shown, inwhich device ink is transferred from a fountain roller 1 to a roller 2having a screen-equipped printing plate from which ink is transferred toa rubber faced roller, not shown, which in turn effects printing of apaper. In the chain between the fountain roller 1 and the printing plateroller 2, a plurality of rollers 3 are present, three of which areconnected to oscillation devices 4 that have the purpose of spreading orevening out the ink layers on the appurtenant rollers by setting theserollers in reciprocating axial motions. Between the two oscillatablerollers shown to the left in FIG. 1 and the printing plate roller 2,four inking cylinders 5 of different diameters are arranged, whichdistribute the ink in the circumferential direction.

Reference is now made to FIG. 2, which partially illustrates anoscillatable roller 3. At each one of the opposite ends thereof, saidroller has a trunnion 6 that is mounted in a frame plate 7. In otherwords, the roller extends between two such, vertical frame plates 7,which together form a solid frame for an offset printing press.

At the outside of the frame plate 7, an oscillation device 4 accordingto the invention, is mounted, which device comprises a housing generallydesignated 8, which is fixedly attached to the frame plate 7 by means ofa screw joint 9.

Inside the housing 8, a reduction gear, in its entirety designated 10,is arranged, which in this preferred embodiment is in the form of aneccentric gear. The roller 3 is rotatable around a geometrical main axisof rotation R. At the end thereof shown to the right in FIG. 2, thereduction gear 10 has a coupling part 11 that is concentric to the mainaxis of rotation R, which coupling part 11 comprises a partiallycylindrical and partially conical body 12 and in the extension a stud 13having a male thread is found, which male thread is screwed into afemale thread in a central recess in the trunnion 6. The conical surfaceof the body 12 is wedged in a seating surface of a corresponding conicalshape when the male thread is tightened in the female thread. On theoutside of the trunnion 6, a ring 14 is arranged, which via a ballbearing 15 is radially journalled relative to the inner part of thehousing 8 that is mounted in a through hole 16 in the frame plate 7. Thetrunnion 6 is axially movable to-and-fro relative to the ring 14. Inother words, the roller 3 may not only rotate relative to the frameplate, but also move axially to-and-fro at a certain length of stroke oroscillation amplitude.

At the left, outer end thereof, the eccentric gear 10 is connected to atransmission member, in its entirety designated 17, which is rotatableas well as axially moveable relative to the housing 8. The transmissionmember 17 is connected to a rotor element, in its entirety designated18, which is rotatably journalled relative to the housing 8. Moreprecisely, the transmission member 17 is connected to the rotor element18 via a hinge 19. The gear 10 has the purpose of gearing down therotation of the roller 3 to a slower rotation of the transmissionmember. In practice, the roller may operate at a rotational speed withinthe range of 800-3000 rpm while the transmission member 17 should notoperate at a rotational speed exceeding 200 rpm. In other words, thegear 10 should have a gear ratio within the range of 4:1 to 15:1.

Eccentric gears of the type that is illustrated in the preferredembodiments of the invention are previously well known within thetechnical area in question. Essential components of the gear is aneccentric body 20 that converts the genuine rotating motion of thetrunnion 6 to a nutating motion of a transmission sleeve 21. As moreclearly appears from the enlarged section in FIG. 5, said transmissionsleeve 21 has an external tooth rim 22 that by only one or just a fewteeth is in engagement with an internal tooth rim 23 of a ring 24. Theeccentric body 20 is integrated with a shaft 25, the left or outer endof which is rotatably journalled relative to the transmission member 17via a bearing 26. Torque from the transmission sleeve 21 is transferredto the transmission member 17 via a ball or arch-tooth coupling 27.

The use of an eccentric gear 10 as a reduction gear is not vital to theimplementation of the invention, and therefore the function thereof isnot described in further detail. The essential thing is that the gear iscapable of gearing down the high rotational speed of the roller to amoderate rotational speed of the transmission member. However, in thisconnection it should be pointed out that an advantage of eccentric gearsin particular, compared to other reduction gears, such as planetarygears, is that the same in a single step can ensure large gear changes(10:1 or larger).

Reference is now primarily made to FIG. 5 that illustrates the essentialof the invention in an enlarged scale.

Above-mentioned transmission member 17 is made up of two subcomponents,viz. a sleeve 28 that partially enclose the eccentric gear 10 and that,in the example, is rotatably journalled relative to the housing 8 via aroller bearing 29 as well as a front piece 30 that is connected to thesleeve 28 via a screw joint 31. The roller bearing 29 is in turnslidably journalled relative to the housing to be able to move axiallyto-and-fro therein. In this context it shall be pointed out that thebearing 29 may be accomplished in another way than in the shape of aroller bearing or even be managed without.

According to the invention the housing 8 that accomodates the gear 10and the transmission member 17 is made up of a fixed wall shell 32 aswell as a casing 33 that is turnable relative to the wall shell 32. Moreprecisely the casing is connected to the wall shell via a circularbearing 34, preferably in the shape of an annular ball bearing. Thefixed wall shell 32 that is bolted to the frame plate 7, hasadvantageously cylindrical primary form and a diameter that does notexceed the diameter of the roller 3.

The aforementioned rotor 18 comprises a structural element designated 35as well as a trunnion 36 that is rotatably journalled in a recess 37 inthe casing 33, more precisely via two bearings 38, suitably rollerbearings, which allows rotation of the trunnion, but prevents that thesame moves axially. Apart from a bottom part 39 and a back piece 40, thestructural element 35 comprises two side walls 41 one of which isvisible in FIG. 5. In FIG. 7 both side walls 41 are shown in an enlargeddetail section, that certainly is inserted as a section A in thealternative embodiment according to FIG. 6, but illustrate the same typeof rotor and hinge as in FIGS. 2-5. The hinge, in its entiretydesignated 19, is made up of a bar 42, e.g. a cylindrical rod, thatextends between the side walls 41 as well as a ball or ball body 43applied to the bar, which ball present a partially spherical shapedsurface. The ball 43 is slidably journalled in a ring 44 having a seatwhich is spherically shaped in an analogous way. The ring 44 is fixedinside an outer sleeve 45 that is associated with a cylindrical pin 46.This pin is in turn rotatably journalled in a through bore 47 in thefront piece 30 of the transmission member 17, more precisely by means ofat least two axially separated bearings 48 in the form of rollerbearings. These bearings 48 allows not only rotation of the cylinder pin46, but also axial motions to-and-fro in the bore 47. It should beobvious that the cylinder pin 47 serves as a carrier for the sleeve 45and the ball 43.

In the preferred embodiment (see primarily FIG. 5) the casing 33 has theshape of an asymmetrical cone relative to the annular bearing 34, in thetapered end of which cone the recess 37 for the trunnion 36 is arranged.The rotor 18 is rotatable around a secondary geometrical axis ofrotation S, which is defined by the trunnion 36 and the position ofwhich relative to the main axis of rotation R. The circular plane P, inwhich the bearing 34 is located, is shown with a dashed and dotted lineand is tilted in an obtuse angle α to the main axis of rotation R. Inthe example, the angle amounts to approximately 115°, though also other,larger as well as smaller angles are considerable. However, the angle αshould amount to, on one hand, at least 110′ and, on the other hand, atmost 120°. Furthermore, the secondary axis of rotation S for the rotorelement 18 is tilted in an angle β to the circular plane P of thebearing 34. In the preferred embodiment according to the invention theangle β provide a supplementary angle to the angle α. In other words theangle β amount to 75° provided that the angle α amount to 115°.

When the rotor 18 rotates the hinge 19 will move in a circular planetarypath which is indicated by means of the dashed and dotted line T in FIG.3. This planetary path T extends in a right angle to the secondary axisof rotation S and is tilted relative to the main axis of rotation R inan acute angle γ in the adjustment position shown in FIGS. 3 and 4,which angle, in the example, amounts to approximately 60°. In otherwords the angle (complementary angle) between the axes R and S amountsto 30°. In the embodiment shown in FIGS. 2-5 the cylinder pin 46together with the appurtenant bore 47 in the front piece 30 extends in aright angle (90°) to the main axis of rotation R. This implies that thecylinder pin 46 form a 30° angle to the planet path T. Furthermore, itshall be pointed out that the structural element 35 of the rotor 18 ingeneral is tilted in an acute angle (not shown) to the trunnion 36. Inthe example, the acute angle amounts to approximately 15°, but may varyupwards as well as downwards.

As is seen in FIG. 5, the secondary axis of rotation S intersect themain axis of rotation R in a point where the plane P of the annularbearing 34 intersect the main axis of rotation. More precisely, saidpoint of intersection form at the same time the midpoint of the circledefined by the bearing 34.

At the outside of a cylindrical end section 49 of the casing 33 (seeFIG. 5) a ring is applied, which has a conical shaped gear rim 50. Arotatable gearwheel 51 is engaged with the gear rim 50, and operatableby means of a power source 52, preferably in the form of an electricmotor, e.g. a simple diminutive alternating current motor. The controlof the operation of the motor is done by means of an inductivenon-contact sensor 53 that in a suitable way (e.g. by means of notchesor recesses in the gear rim or in the gear rim ring) may read the actualangle of rotation position of the casing relative to the wall shell 32.Thus, by means of the motor the casing 33 may, with great accuracy, betrimmed in desired position relative to the fixed wall shell 32.

The Function of the Device According to the Invention

Presuppose that the roller 3 (see FIGS. 3 and 4) rotates at 2400 rpm andthat the eccentric gear 10 has a gear ratio of 12:1. In such a case, thetransmission member 17 will rotate at 200 rpm, i.e. in this context amoderate rotational speed. During the rotation of the transmissionmember 17, the hinge 19 between the transmission member and the rotor 18will compulsorily convey axial motions to-and-fro to the transmissionmember, more precisely as a consequence of the casing 33, serving as aholder for the rotor, being fixed or immobile in the appointed settingposition thereof. Accordingly, during the first half of a revolution,the hinge 19 in the setting position of the casing 33 according to FIGS.3 and 4 will move from the position shown at the bottom of FIG. 3 to theposition shown at the top of FIG. 4. Thanks to the secondary axis ofrotation S for the rotor 18 forms an acute angle that amounts to 30° tothe main axis of rotation R in the actual setting position, the hinge 19will also move in the axial direction during the revolving motion of therotor and thereby compulsorily convey the transmission member 17 in thesame direction. During the first half of a revolution, the hinge andthereby the transmission member will move from an inner end positionaccording to FIG. 3 to an outer end position according to FIG. 4, theroller 3 being conveyed between the inner and the outer end positions aswill be seen clearly on a comparison between FIG. 3 and FIG. 4. Duringthe next half of revolution, the hinge, the transmission member and theroller will move from the outer end position according to FIG. 4 back tothe inner end position according to FIG. 3. In doing so, the length ofstroke of the transmission member and thereby also the axial length ofstroke of the roller are determined by the angle between the main axisof rotation R and the planet path T for the hinge 19, more precisely insuch a way that an increasing angle lead to a decreasing length ofstroke and vice versa.

Reference is now made to FIG. 2, that show the casing 33 set in an angleof rotation position in which the secondary axis of rotation S for therotor 18 coincide with the main axis of rotation R. In this case theplanet path T for the hinge 19 is oriented in a right angle to the mainaxis of rotation R, whereby neither the transmission member 17 nor therotating roller moves axially. In other words the length of stroke, inthis condition, is equal to zero.

Thanks to the fact that the casing 33 may be turned to an arbitraryangle of rotation position between the primary position according toFIG. 2 and the maximum turned position according to FIGS. 3 and 4, thetilting angle of the planet path T may be trimmed from small to bigoscillation amplitudes. Similar readjustments of the oscillationamplitudes may be realized in a simple way even during operation thanksto the simple action of activating the motor 52 through remote controlso that the same via the planet wheel 51 (and a housed gear) will conveythe casing to turn a desired number of degrees relative to the wallshell 32. Another advantage with the device according to the inventionis that the same allows to be designed having a minimal volume to beable to be mounted externally on a roller frame in a simple way withoutcausing troublesome component collisions. In this respect the diminutivemotor 52 does not cause problems thanks to the fact that the same atfixation of the wall shell 32 may be located in any angle of rotationposition in the periphery area of the housing. Furthermore, the designdetails which are necessary for the oscillation movements, are housed ina sealed housing from which lubricant does not risk to splash or leakout. Thanks to the fact that the oscillation amplitude of the device maybe remotely controlled in an instant and uncomplicated way, the need ofshutting down the offset printing press during required readjustmentoperations disappear.

Reference is now made to FIG. 6, that illustrates an alternativeembodiment which only differs in design from the embodiment shown inFIGS. 2-5 in that the cylinder pin 46 for the hinge 19 is oriented inanother angle than 90° to the main axis of rotation R. More precisely,the cylinder pin together with the associated bore in the front piece 30being oriented in a right angle to the secondary axis of rotation S.When the hinge 19 rotate in its planetary path the cylinder pin willtherefore move axially to-and-fro in the bore without being subject toany lateral forces.

Feasible Modifications of the Invention

The invention is not limited only to the embodiments described above andshown in the drawings. Thus, it is theoretically possible to use othertypes of reduction gears than exactly eccentric gears. Furthermore, therotor as well as the transmission member and the hinge between thesecomponents may be designed in different ways within the scope of thefollowing claims.

1. Device for conveying oscillating axial motions to a roller (3) whichis rotatable around a geometrical main axis of rotation (R) and which ismounted in a frame (7), comprising a reduction gear (10), which isconnectable to the roller (3) and connected to a transmission member(17) being rotatable around the main axis of rotation and simultaneouslymoveable axially to-and-fro in order to gear down the rotation of theroller to a slower rotation of the transmission member, transmissionmember being connected to a rotor (18) being rotatably journalled in aholder (33), around a secondary axis of rotation (S) via a hinge (19)being radially spaced from the main axis of rotation (R), hinge beingplanetary moveable in a path (T), the angle (y) of which relative to themain axis of rotation (R) determines the axial length of stroke of thetransmission member and thereby the axial length of stroke of theroller, characterized in that the reduction gear (10) and thetransmission member (17) are housed in a housing (8) that comprises afixed wall shell (32) as well as a casing (33) serving as a holder forthe rotor, said casing being turnable relative to the wall shell topro-vide readjustment of the angle of the guide path (T) relative to themain axis of rotation (R) and thereby the axial length of stroke of theroller (3).
 2. Device according to claim 1, characterized in that thecasing (33) is turnable relative to the wall shell (32) via a circularbearing (34) the circular plane (P) of which is tilted to a first angle(a°) relative to the main axis of rotation (R), and that the secondaryaxis of rotation (S) for the rotor (18) is tilted relative to thecircular plane of the bearing (34) to a second angle (fig), that forms asupplementary angle to the first angle, whereby the secondary axis ofrotation (S) is adjustable in a starting position coaxially to the mainaxis of rotation (R) and in which posi-tion the planet path (T) of thehinge (19) is oriented in a right angle to the main axis of rotation (R)and the length of stroke of the roller is equal to zero.
 3. Deviceaccording to claim 1, characterized in that the rotor (18) comprises atrunnion (36) which is rotatably journalled in a recess (37) in thecasing (33) and which defines said secondary axis of rotation (S) aswell as a structural element (35) which is oriented in an acute anglerelative to the trunnion and which comprises two separated side walls(41) between which a bar (42) extends that defines the position of saidhinge (19).
 4. Device according to claim 3, characterized in that thehinge (19) comprises a ball (43) in addition to said bar (42), said ballbeing turnably journalled in a seat in a holder (44,45, 46) that isconnected to the transmission member (17).
 5. Device according to claim4, characterized in that the holder comprises a cylindrical pin (46)which is turnably journalled in a bore (47) in the transmission member(17) and axially movable to-and-fro therein.
 6. Device according toclaim 5, characterized in that the cylinder pin (46) extends at a rightangle to the main axis of rotation (R).
 7. Device according to claim 5,characterized in that the cylinder pin (46) extends at a right angle tothe secondary axis of rotation (S).
 8. Device according to claim 3,characterized in that the casing has the shape of a cone (33) which isasymmetric relative to the circular bearing (34), and in the tapered endof which the recess (37) for the trunnion (36) is arranged.
 9. Deviceaccording to claim 2, characterized in that the secondary axis ofrotation (S) intersect the main axis of rotation (R) in a point wherethe midpoint of the circular bearing (34) is located.
 10. Deviceaccording to claim 1, characterized in that a circular gear rim (50) isconnected to the casing (33), a rotatable gear wheel (51) interacts withthe gear rim, said gear wheel being operatable by means of a motor (52)and the function of which is to pro-vide turning of the casing betweenarbitrary angle of rotation positions relative to the wall shell (32).11. Device according to claim 10, characterized in that an inductivesensor (53) interacts with the gear rim (50) to control the operation ofthe motor (52).
 12. Device according to claim 2, characterized in thatthe rotor (18) comprises a trunnion (36) which is rotatably journalledin a recess (37) in the casing (33) and which defines said secondaryaxis of rotation (S) as well as a structural element (35) which isoriented in an acute angle relative to the trunnion and which comprisestwo separated side walls (41) between which a bar (42) extends thatdefines the position of said hinge (19).